Abstract

Semiconductor quantum wells have been used to produce efficient optoelectronic devices that use the quantum-confined Stark effect (QCSE). Both the rise time and the recovery of these devices after optical excitation are dependent on the escape of free carriers from the wells.^1–4 The principal mechanism for carrier removal from an individual well is believed to be thermionic emission. In multiple-quantum- well structures the ability to distinguish between the transient effects of electrons and holes is complicated by effects such as resonant tunneling and carrier retrapping. Furthermore, the presence of multiple wells precludes the direct application of a simple thermionic-emission model. Carrier lifetimes for each carrier type can be compared with a thermionic-emission model by monitoring the separate contributions of the electrons and holes through the dynamics of the QCSE and exciton saturation. In this paper we present simultaneous time-resolved measurements of electron and hole escape times in single-quantum-well asymmetric-barrier p-i-n-doped waveguide structures as a function of temperature for the first time to our knowledge.

© 1993 Optical Society of America